(PS1-43) Predictors of Attrition in Integrated, Trauma-focused Therapy for Co-occurring PTSD and Alcohol Use Disorder

Posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD) commonly co-occur in veterans and civilians. Interventions for comorbid PTSD/AUD are effective, but attrition is problematic. Treatment completion is associated with improved clinical outcomes; therefore, identifying ways to enhance retention is essential. Concurrent Treatment of PTSD and Substance Use Disorders using Prolonged Exposure (COPE) is an integrated 12-session, trauma-focused, cognitive-behavioral, outpatient therapy that is efficacious in reducing symptoms of PTSD and AUD. The current study is a preliminary investigation of predictors of attrition using data from an ongoing double-blind, randomized controlled trial evaluating COPE plus oxytocin versus placebo among veterans with current DSM-5 diagnoses of PTSD/AUD (N = 109). Participants who completed or had been enrolled long enough to complete the treatment phase of the trial were categorized as treatment completers (attending 8 or more sessions; n = 60) or non-completers (7 or fewer sessions; n = 49). Baseline demographic variables and clinical symptoms, measured by self-report and clinician-administered assessments of PTSD (CAPS-5; PCL-5), AUD (AUDIT; TLFB), and depression (BDI-II), were examined as predictors of attrition. We hypothesized that greater severity of baseline symptoms would be associated with increased attrition.  Independent samples t-tests, chi-square tests, and multivariable logistic regression models were conducted. Findings revealed that years of education was the only significant predictor of attrition, with treatment completers reporting greater education (M = 15.2, SD = 2.8) than non-completers (M =13.9, SD = 2.1; t(107) = 2.69, p = .01). Thus, individuals with fewer years of education were less likely to remain in treatment. Data collection is ongoing, and treatment group assignment (oxytocin or placebo), which is also hypothesized to influence treatment attrition, remains blinded. Although preliminary, the findings may help identify patients who would benefit from additional support to enhance retention. Additional research is needed to examine predictors of attrition more fully in the complete sample and develop effective methods to enhance retention in trials such as this.